girard



-2 Sheets-Sheet 1 A. G. GIRARD 85 E. A. G. STREET.

(No Model.)

ELECTRIC FURNACE.

Patented No v. 17, 1896.

(No Model.) I 2 Sheets-Sheet 2. A. O. GIRARD & E. A. G. STREET ELECTRICFURNACE.

Patentd Nov. 17, 1896.

w w v w a 0 a a "a fl Witneooao UNITED STATES ADAM CHARLES GIRARD ANDERNEST AUGUS"E GEORGES STREET, OF

PARIS, FRANCE.

ELECTRIC FURNACE.

SPECIFICATION forming part of Letters Patent No. 571,655, dated November17', 1896.

Original application filedMay 24, 1895, Serial No. 550,538. Divided andthis application filed October 29, 1895. Serial No.

567,273. (No model.) Patented in France May 25, 1893,1T0. 230,341; inEngland July 8, 1893,110. 18,3 in Germany August 2, 1893, No. 81,479; inAustria-Hungary August 2, 1893,1l0. 41,930 and No. 65,879; in Belgium8eptember 9,1893,1T0.106,309; in Switzerland September 14,1893, Nos.8,017 and 8,689; in Italy September 30,1893,

No. 267, and in Spain October 2'7, 1898, No. 1 1,950.

Be it known that we, ADAM CHARLES G1 1 HARD, chemist, residing at 7 Ruedu Bellay, and ERNEST AUGUSTE GEORGES STREET, engineer, residing at RueJoubert, Paris, France, citizens of the Republic of France, haveinvented certain new and useful 1mprovements in and Relating to ElectricFurnaces, (for which we have obtained patents in France, No. 230,341,dated May 25, 1803, certificate of addition thereto dated June 8, 1803;in Great Britain, No. 13,340, dated July 8, 1803; in Germany,certificate of addition No. 81,470, dated August 2, 1803; inAustriallungary, No. 41,030 and No. 65,870, dated August 2,1803; inSwitzerland, Nos. 8,017 and 8,680, dated September 14, 1803; in Belgium,No. 100,300, dated September 0, 1803; in Spain, No. 1%,950, datedOctober 27, 1803, and in Italy, No. 267, dated September 30, 1803,) ofwhich the following, origin ally forming part of the application, SerialNo. 550,538, filed on May 24, 1805, is a specification, reference beinghad to the accompanying drawings, forming part thereof.

This invention relates to electric furnaces which are more particularlyadapted for heat ing fusible materials, and has special reference to theclass of electric furnaces described in our application for patent,Serial No. 550,538, filed on the can day of May,1805.

In order that our invention may be clearly understood, we will describethe same with reference to the accompanying drawings, in which- Figure 1is a vertical section of an electric furnace constructed in accordancewith our present invention.

Fig. 2 is also a vertical section of a modified form of the furnace.

Fig. 3 is a similar view in section, showing the carbon tube or crucibleas being heated by two pairs of electrodes, in which case four arcs areprovided instead of two, these four ares being two by two in series, inthe first series one are being from carbon (l to tube 6, second are fromtube 6 to carbon d, and in the second series one are being from carbon(Z to tube 6 and second are from tube (2 to carbon d". It may be easilyunderstood that the longer the tube (2 is made and the greaterheatii'ig-surface is desired the more pairs of arcs are employed.

Fig. 1 shows a tube of enlarged diameter and represents a cross-sectionof the central part of the furnace, wherein two series of arcs aregrouped two by two in the same circuit. It will be understood that fortubes of still larger diameter more than two pairs of arcs may beemployed, said ares being placed all around the tube (2.

Fig. 5 represents a sectional view wherein a rotating are is used. Theletter cindicates the carbon tube, and s s are two electrodes pierced attheir inner end portion with circular holes or orifices concentric withthe carbon tube and through which said tube extends. A magnetic field isproduced by two electric magnets or solenoids M and M. The electric arcplays on the surface of carbon tube 6, and the surfaces of the holes oropenings in the electrodes 5' and s and the magnetic field causes thearc to rotate around the carbon tube c. In other words, the lines offorce in the magnetic field being at right angles to the faces of thepole-pieces of the magnets M and M the voltaic are may be represented bya line or lines at right angles to the lines of force. Thus the are,being a current flowing at right angles to the lines of force, willrevolve about the center of the field with a velocity depending on thestrength of the latter, the principle being similar to that in theFaraday disk or Barlow wheel. The current employed is a continuous oneand enters by s in the furnace and leaves by a, or the inverse.

Fig. 0 is a detail sectional view of one of the concentric electrodesdescribed.

Like letters of reference indicate similar parts in all the figures.

a is an internal block composed of some refractory material that is abad conductor of heat. 0 is an external casing, preferablymetallic,which surrounds the internal block a. This block (L may be formed in oneor more parts and is provided with an internal cavity 0, whichconstitutes the heating-chamber proper. This cavity is preferably formedin a block of carbon arranged within the aforesaid surroundingrefractory block a. d d are two carbon electrodes, whose inner endsproject into the said cavity 0 and come into proximity to an innercarbon tube a, which serves both as a crucible or receptacle for thematerial to be heated and as one of the electrodes for the arc.

The heating is effected by means of two arcs in series or by means ofseveral groups of two arcs in series, as seen in Figs. 3 and 1-. One arcis formed between the carbon electrodes (l and the carbon tube orcrucible 6, while the other are is formed between the said tube orcrucible and the second carbon electrode d. The material to be treatedis introduced through a hopper f at the upper part of the furnace, whichhopper is closed with a cover f the said material being withdrawn fromthe lower part of the furnace. The coverf is sealed by a hydraulic orother seal to effectually close the upper part of the furnace throughthe hopper. Special arrangements may be employed for effecting thewithdrawal and introduction of the materials according as they are in asolid, liquid, or gaseous condition after their passage through thefurnace. Any suitable gas may also be introduced or circulated throughthe furnace or through the material during its passage through thefurnace. The gas employed may be introduced through an inlettube 9 atthe upper part of the furnace and be conducted away through theoutlet-orifice 71 The size of this outlet may be so regulated that thematerials can be caused to pass through the furnace at any desiredspeed, so that they can thus be kept in the furnace for any requiredlength of time. The gas may in some cases be introduced and dischargedthrough the carbon electrodes themselves, in which case the saidelectrodes are made hollow, as shown in the drawings.

\Vhen fusible materials are to be treated, we employ a furnace having ahearth i, Fig. 2, made of suitable material, to receive the fusedsubstances and also having an outletj, which latter may be so arrangedthat notwithstanding said outlet the special gas employed in the heatingoperation can be retained in the furnace as long as desired.

It will be obvious that a rotating are produced in the manner describedin our beforementioned application for patent can be used in thefurnaces above described. I11 this case the carbon tube or crucible cwould be surrounded by one or more carbon disks arranged concentrictherewith and insulated from each other, the arcs produced between thesedisks and the said tube or crucible e being sub jected to the action ofa magnetic field, as described in the aforesaid application for patent.

Having now described our said invention and in what manner the same isto be performed, we claim 1. An electric furnace having a fixed car bontube or casing through which the material to be heated is fed, saidcarbon tube or casing constituting a common electrode, and one or moreother electrodes arranged in proximity to said carbon tube to produce anarc out-side of said tube, whereby the material under treatment isseparated from the are, substantially as described.

2. In an electric furnace having ahcatingchamber for treating fusiblematerials, the combination of a carbon tube or casing locat-ed in saidheating-chan'lbcr and constituting one of the electrodes between whichthe arc is produced, carbons (I, d constituting other electrodes, ahearth, such as 1 located in juxtaposition to the inner end portion ofthe carbon tube or casing and in which the material, as it is fused,collects, and an outlet or conduit communicating with said hearth andthrough which the fused material can be discharged, substantially asdescribed.

3. An electric furnace having a refractory block (1, provided with aheating-ehambcr c, and a longitudinal passage, a hopper connected withthe upper end of said passage and provided with a coverfat its upper endand with an outlet 7t at its lower end, a carbon tube 0 located withinthe heating-chamber, carbon electrodes (1 and (1 arranged about thecarbon tube for producing a voltaic are outside said tube and enablinggaseous fluid to be conducted to the heating-chamber, and a tube 9opening into said hopper, substantially as described.

4. An electric furnace having a refractory block a provided with aheating-chamber c, and a longitudinal passage, a hopperfconnected withthe upper end of said passage and provided with a cover f, a carbon tube6 located in the heating-chamber, electrodes (1 and d arranged about thecarbon tube for producing a voltaic are outside said tube, a hearth 1'-located in juxtaposition to the inner end of the carbon tube, and adischargeoutlet j, substantially as described.

In witness whereof we have hereunto set our hands this 20th day ofSeptember, 1805.

ADAM: CHARLES Glliiilil). ERNEST AUGUS'IE GEORGES S'llilll-l'l.

\Vi tnesscs:

JEAN ALBERT Lanny, PAUL JEAN GIRARD.

